The present invention relates to a sun blind for a window, in particular a window occupying permanently or temporarily a vertical, slanting or a horizontal position and optionally being operative to be toppled about a horizontal axis, said sun blind comprising a horizontal profiled top bar fastened to or integrated with the header of the window frame, a horizontal profiled bottom bar operative to be moved with respect to said top bar, a sun blinding portion between said top bar and said bottom bar, lateral guides for guiding the ends of the bottom bar, said guides being provided along or within the side posts of the window frame, at least two cords running through apertures in the sun blinding portion and optionally an additional profiled bar along the bottom sill part of the window frame.
Sun blinds of this type are well known in practice and from the literature. As far as the present invention is concerned the construction of the sun blinding portion is quite immaterial. This sun blinding portion may for instance be in the shape of a pleated cloth, a Venitian blind having horizontal slats, a blackout curtain, an energy screen and the like.
In general it is more difficult to apply sun blinds for a window positioned in an oblique plane than for a window mounted in a vertical plane of a frontispiece. Many of such windows mounted in an oblique plane may moreover also be toppled about a horizontal axis in the window frame. This capability of being toppled may be necessary or desired in view of ventilation or cleaning purposes. This inversion or toppling capability of the window leads to an additional complication with respect to the application of a sun blind.
The known sun blinds for vertical windows are operated by cords for drawing up, i.e. two or more cords the ends of which are fastened to the profiled bottom bar and which may be hauled in for opening the sun blind. Through apertures in the sun blinding portion the cords run upwards to the profiled top bar and then through the top bar to one side of the window. Although this construction is quite satisfactory in case of vertical windows it is less suitable for windows in a slanting position and even less if the windows may moreover be toppled about a horizontal axis. In the latter case the profiled bottom bar should be capable moreover of fixation in the guides in any adjusted position. This fixation should furthermore be maintained upon changes in the position of the window and consequently of the sun blind. Accordingly there is sometimes provided a mechanical locking means for locking the end of the profiled bottom bar in the side guides.
The operation of the cords for drawing up is often very difficult especially when the window occupies a substantially horizontal position. When drawing up or lowering the sun blind it is moreover difficult to keep the bottom bar parallel to the top bar. Consequently the profiled bottom bar will often occupy an oblique position this not benefiting the appearance of the window, while upon hanging in a oblique position there is moreover quite some chance that the cords will be loaded heavier and will consequently be subject to increased wear and even breakage. The stowing away of the cords for drawing up next to the window forms an additional complication.
In case of sun blinds for windows having a larger width it will be required to provide apart from the left hand and right hand cords additional guiding cords in the middle or at several locations. In some sun blinds of the known types these guide cords also function as cords for drawing up. In other known types there are additional cords, steel wires or plastic threads as guide means. These additional cords and the like are then usually fastened in the profiled top bar of the sun blind, while running down through the sun blinding portion and the bottom bar and being fastened to the sill part of the window frame. These cords have the drawback that they will also remain in front of the window pane when the sun blind has been drawn up completely, this being very awkward in practice, for instance when cleaning the inside of the window pane. Moreover these cords very soon lose the taut condition thereof and are very often subject to breakage. In practice there is usually chosen the solution in which the additional guide cords also function as cords for drawing up but in that case it is of importance that the sun blind as such consists of a material having a substantially high stiffness so that in case of a Venetian blind the slats have to be made of aluminum or a rigid plastic.